I've been skeptical myself about the incredibly high figures for mortality in Iraq since the invasion quoted by the Lancet study -- they are after all several times higher than other sources -- but the BBC has obtained (through a freedom of information request) a formerly confidential report from the UK's top government scientist who said the methodology used in the Lancet article is credible:

The British government was advised against publicly criticising a report estimating that 655,000 Iraqis had died due to the war, the BBC has learnt.

Iraqi Health Ministry figures put the toll at less than 10% of the total in the survey, published in the Lancet.

But the Ministry of Defence's chief scientific adviser said the survey's methods were "close to best practice" and the study design was "robust".

Another expert agreed the method was "tried and tested".

The Iraq government asks the country's hospitals to report the number of victims of terrorism or military action.

Critics say the system was not started until well after the invasion and requires over-pressed hospital staff not only to report daily, but also to distinguish between victims of terrorism and of crime.

The Lancet medical journal published its peer-reviewed survey last October.

It was conducted by the John Hopkins School of Public Health and compared mortality rates before and after the invasion by surveying 47 randomly chosen areas across 16 provinces in Iraq.

The researchers spoke to nearly 1,850 families, comprising more than 12,800 people.

In nearly 92% of cases family members produced death certificates to support their answers. The survey estimated that 601,000 deaths were the result of violence, mostly gunfire.

Shortly after the publication of the survey in October last year Tony Blair's official spokesperson said the Lancet's figure was not anywhere near accurate.

He said the survey had used an extrapolation technique, from a relatively small sample from an area of Iraq that was not representative of the country as a whole.

President Bush said: "I don't consider it a credible report."

But a memo by the MoD's Chief Scientific Adviser, Sir Roy Anderson, on 13 October, states: "The study design is robust and employs methods that are regarded as close to "best practice" in this area, given the difficulties of data collection and verification in the present circumstances in Iraq."

While this is not necessarily conclusive about the Lancet study, it is pretty damning about the mendacity of Tony Blair's cabinet. But then again we knew that already. Here is another BBC analysis, dated October 2006, that looks at the competing estimates of Iraqi deaths.

Issandr El Amrani is a Cairo-based writer and consultant. His reporting and commentary on the Middle East and North Africa has appeared in The Economist, London Review of Books, Financial Times, The National, The Guardian, Time and other publications. He also publishes one of the longest-running blog in the region, www.arabist.net.